The detective novel was invented in the 1840s, but it was perfected in 1887. That year saw the publication of A Study in Scarlet, Arthur Conan Doyle's first book to feature his signature character, Sherlock Holmes. Over four decades, Doyle's stories of the preternaturally talented sleuth cemented Holmes as the world's most famous detective.
Over more than 250 portrayals on the stage and screen, Holmes is typically portrayed as brilliant yet cold and aloof, aided by his constant companion, John Watson. Now, after more than 130 years and numerous complicated court cases, Holmes has definitively entered the public domain, meaning that anybody can use the character in a published work. And despite the Doyle estate's protestations, that's a good thing.
